This invention relates to a cab door structure having a door swingable to open and close an entrance to a cab.
A known cab door structure, as disclosed in JP 6-211048, for example, has a door with door glass attached to a door body, which door is swingable fore and aft about an axis of a pivotal support.
In the conventional cab door structure disclosed in the above document, the door in a closed state is sealed by a seal material interposed between the door body and a door frame. To secure good door sealing performance with the door body, door frame and seal material.
In order to place the seal material in tight contact uniformly over the entire circumference of the door body and door frame when the door is closed, it is necessary to manufacture the door body and door frame with sufficient accuracy. To secure rigidity of the door itself and rigidity of the cab, the door body and door frame, generally, are manufactured by plate working of a steel material. However, because of the relatively large size, it has been difficult to manufacture the door body and door frame with sufficient accuracy. Specifically, when welding the door body and door frame, for example, it is necessary to remove welding stress after the welding in order to achieve accuracy. When press forming the door body and door frame, large press dies must be manufactured with sufficient accuracy. Thus, it has been difficult to manufacture the door body and door frame with sufficient accuracy.
Therefore, a construction employed for securing good door sealing performance with the seal material interposed between the door body and door frame, as in the conventional cab door structure, poses a problem of raising the cost of manufacturing the door body, and a problem of taking time in assembling and adjusting operations and increasing man-hour for attaching the door to the door frame, which has been the cause of high manufacturing cost. The above problems are conspicuous particularly in the case of working vehicles having cabs, since the volume of production is small compared with passenger vehicles, and large sums cannot be invested in plant and equipment.